Electric furnace



H. DE NOLLY.

ELECTRIC FURNACE.

APPLICATION FILED APR. s, m2o.

Patented May 23,

1922. 2 SHEETS-'SHEET I.

H. DE NoLLY. ELECTHC FURNACE.

' APPLCATION FILED APR. 8, 1920. 1,417,303.

2 SHEETS-SHEET 2.

Patented May 23, 1922..

UNITED STATES PATENT CFFICE.

HECTOR DE NOLLY, OF LYON, FRANCE, ASSIGNOR T0 LA SOCIETE METALLURGIQUE DU FRAYOL, 0F' LYON, FRANCE.

ELECTRIC rimNAcn Y Specification of Letters Patent.

Patented' May 23,1922.

Application led April 8, 1920. Y Serial No. 372,176.

France, have invented certain new and useful v Im rovements in Electric Furnaces, (for which I- have filed applications in France, January 7, 1920; Belgium, January 10, 1920; Italy, January 9, 1920; Spain, January 16, 1920; Germany, February 5, 1920; Austria, February 17, 1920,) of which the following is a specification.

The present invention relates to electric furnaces for the fusion and refining of metals and other substances.

In the furnace the usual roofing or vaulting constructed of silica is replaced' by a blo'ck of graphite, the height of which can be regulated, said block being constituted by an assemblage of several pieces of suitable shape and size. The upper part of the furnace is provided with a cooling jacket constructed of cast iron or moulded steel and through which water' circulates. Vithin this jacket the block of graphite can slide vertically. I

This construction allows the capacity pf the working chamber to be varied by raising or lowering the block. Or by removing the block the furnace can be completely open at its upper part, if required. v

Further, the invention provides an unwearable vaulting or one that can easily be replaced during working of the furnace, as the silica vaulting usually employed rapidly becomes useless owing to radiation from .the arc, and more particularly to the v0latil1za tion of lime, which is unavoidable when ultra' basic slag as is generally the case is treated.

Further, a tighworking chamber is ob-` tained since in the improved furnace the electrodes do not pass through the vaulting; consequently a reduced atmosphere can be maintained and oxidation ofthe bath becomes impossible. The block of graphite foi-ming the vaulting not having to be continually manipulated to regulate the voltage, a tight joint can be formed by means of clay or other refractory product, packed between the block and the cooling jacket immediately the furnace is working normall The furnace also comprises rther features, notably the position and arrangement of movable electrodes and the employment of lateral conductive plates connected in parallel with a conductive plate provided at the bottom ofthe furnace. These means allow of easy priming starting from a cold charge.

As long as the lining ofthe furnace is not sufficiently hot to be conductive, the return of the current is effected through the lateral conductive plates. For this purpose when being charged the furnace is slightly inclined in such a way that the charge is in contact with the lateral conductive plates. In accordance with the fusion of the substances the sole is heated and when it is suiiiciently conductive, the return current operates through the conductive plate at the bottom of the furnace and it is suiicient then to tilt the furnace in the reverse direction so'that the lateral `conductive plates emerge from the bath.

It is to be observed that with such -arrangement, it is very easy to vary the electric working of the furnace during operation since by simple tilting of the furnace to the right or left, the whole or a part of the current can be caused to pass through the metallic bath orythe slag. j

The furnace may be worked by monophase or triphase currents, the phase displacement found in triphase current fbeing so feeble that it is not industrially harmful.

The annexed drawing shows an example of construction of the furnace.

Fig. l is a longitudinal section on line 1--1 of Fig. 2, of the left side only of the furnace.

Fig. 2 is a transverse section on line 22 of Fig. 1. y

The two round current conducting electrodes a pass into the furnace.through thev end walls of the body of the furnace. These electrodes are cooled by water circulating jackets b. The electric connections of these electrodes is obtained by means of collars c constructed to allow if necessary the rotation of the electrodes round their axes. The voltage is maintained constant by means of small motors al governing the movement of plates.

The supports and trackways g are fixed to the supporting framework of the furnace by means of bolts insulatedby means of micanite, asbestos or any other insulating material.

The water circulation collars b serving for cooling the electrodes are also insulated.

rIhe conductive plate h at the bottom of the furnace, as well as the two lateral conductive plates z do not require special insulation, lthe refractory substances being sufficiently resistant; it is sufficient to make the openings in the iron casing of the furnace a little larger than the section of the connecting heads of these plates.

The connections of the conductive plate h are shown at j and comprise supple cables to allow 'the koscillations of the furnace. Rigid conductors z" are used, however, to connect electrodes z' in parallel with the conductive plate 7L as shown in Fig 2.

The conductors k and Z conveying the current to the electrodes a comprise rigid parts andsupple parts to allow the oscillations of the furnace and to allow the maximum movement of the electrodes a.

The furnace can oscillate on a cradle m having curved ends carrying toothed sectors n supported by rollers working on fixed axles o. An electric motor p effects the oscillating or rocking movements of the furnace.

The blocks g and fr' forming the vaulting are cooled by water circulating jackets s and are suspended by a steel cable t by means of a fixed pulley and an intermediate pulley, the cable being operated by means of a winch fixed on the wall of the furnace.

A safety chain u fixed by a hook to the cross bar fv with a certain play so as not to paralyze the downward movement of the blocks g r forming the vaulting prevents any accident in case of rupture of the steel cable. When these blocks are to be replaced the chains of an electric travelling crane are hooked to two rings which the movable cross bar' v carries. The bar 'v is tilted slightly by the crane'so as to stretch the safety chain in order to allow of unhooking the attachment of the steel cable, and it is then suiiicient to execute. the replacement by means of the electric crane. Under these conditions the change of blocks is eected very rapidly.

For furnaces of large capacity the vault forming blocks are sub-dividedlnto several groups to facilitate operation, each of these groups can be changed separately. Also each group having its operating tackle, the regulation of the height is obtained without difficulty in case of unequal wear.

What I claim as my invention and dcsire to secure by Letters Patent of the United States is l. An electric furnace comprising a body of refractory material open at its upper part, a block of graphite vertically movable in said open upper part and-fittin therein. so as to form a vaulting and forming with said body the reduction chamber of the furnace, means for effecting the movement of said block, inclined movable electrodes passing through the side walls of said body, means for imparting movement to said electrodes, a polar plate at the bottom of said reduction chamber, lateral polar plates mounted in parallel with said bottom polar plate and extending into said reduction chamber, means for conveying electric current to said polar plates and to said electrodes, means supporting said body and means whereby sald body can be rocked upon said supporting means.

2. An electric furnace comprising a body of refractory material open at its upper part, a block of graphite vertically movable in said open upper part and fitting therein so as to form a vaulting, and forming with said body the reduction chamber of the furnace, pulley mechanism for-lifting or lowering said block, means for cooling said block, inclined movable electrodes 'passing through the side walls of said body, means for cooling said electrodes, collars surrounding said electrodes, carriages connected to said collars, rails supporting said carriages, means for moving said carriages on said rails and thereby said electrodes, a polar plate at the bottom of said reduction chamber. lateral polar plates mounted in parallel with said bottom polar plate and extending into said reduction chamber, means for conveying electric current to said polar plates and to said electrodes, means supporting said body and means'whereby said body can be rocked upon said supporting means.

3. An electric furnace comprising a body of refractory material open at its upper part, a block of graphite vertically movable in said open upper part and fittin therein so as to form a vaulting, and forming with said body the reduction chamber of the furnace, pulley mechanism for lifting or lowering said block, means for cooling said block, inclined movable electrodes passing through the side walls of said body, means for cooling said electrodes, collars surround- 1n said electrodes, carriages connected to said collars, rails supporting said carriages, means for moving said carriages on said imparting rotation to said shaft to rock said body on said base through said toothed wheels and curved racks. l

In witness whereof` I have signed this 1 specification in the presence ofv two wit- 15 nesses.

HECTOR DE NOLLY.

Witnesses DOMINIQUE MILLIAND, JEAN GERMAIN. 

